Ordered vertically oriented porous inorganic films produced through solution processing

Abstract

Porous films with straight pores oriented normal to the plane of the films are produced through solution processing techniques. The production takes advantage of inorganic-surfactant or inorganic-polymer co-assembly and a patterned substrate. The patterned substrate, which is also produced via solution phase self-assembly, forces vertical orientation in a hexagonal cylinder system with no practical limits in substrate size or type. This provides a route to vertically oriented inorganic pores with a pitch ranging from 3 nm to over 15 nm and pore sizes ranging from 2 nm to over 12 nm. The size is tuned by choice the choice of organic templating agents and the deposition conditions. The pores can be produced with or without a capping layer which can be used to seal the nanopores.

1. A method for producing an inorganic film having pores oriented normal to the plane of a surface of the film, comprising;
 forming a pattern of contrasting hydrophobicity and/or hydrophilicity on the film surface; 
 growing an inorganic/organic composite layer, by inorganic/organic co-self-assembly, on the patterned surface, in which the composite layer comprises any polymer or surfactant templated hexagonal patterned material grown on any polymer or surfactant templated cubic patterned material, whereby the composite can conform to the surface pattern to form vertically oriented pore structures; and 
 treating the composite to remove the organic part of the composite to form a pattern of pores corresponding in location to said pattern. 
 
     
     
       2. The method of  claim 1  in which the surface pattern is made up of hydrophobic patches on a hydrophilic film surface. 
     
     
       3. The method of  claim 1  in which the surface pattern is made up of hydrophilic patches on a hydrophobic film surface. 
     
     
       4. The method of  claim 1  in which the inorganic/organic composite is formed by self-assembly. 
     
     
       5. The method of  claim 1  in which the components are formed by crosslinking, then calcining, the self-assembled components. 
     
     
       6. The method of  claim 1  in which the film surface is flat. 
     
     
       7. The method of  claim 1  in which the composite layer comprises silica on a titania patterned surface. 
     
     
       8. The method of  claim 1  in which the film is an oxide film. 
     
     
       9. A method for producing an inorganic film having pores oriented normal to the plane of a surface of the film, comprising;
 forming a pattern of contrasting hydrophobicity and/or hydrophilicity on the film Surface; 
 growing an inorganic/organic composite layer, by inorganic/organic co-self-assembly, on the patterned surface whereby the composite can conform to the surface pattern to form vertically oriented pore structures, in which the surface pattern is formed from a cubic patterned self-assembled material, and in which the vertically oriented pore structures are hexagonally arranged, the surface pattern on the film being hexagonal with a close lattice match to the composite; and 
 treating the composite to remove the organic part of the composite to form a pattern of pores corresponding in location to said pattern. 
 
     
     
       10. The method of  claim 9  in which the film is an oxide film. 
     
     
       11. A method for producing an inorganic film having hexagonally arranged pores vertically oriented normal to the plane of a surface of the film, comprising;
 forming a pattern from a cubic patterned self-assembled material on the film surface, the pattern having contrasting hydrophobicity and hydrophilicity, and crosslinking the components to form a flat surface; 
 growing an inorganic/organic composite, by inorganic/organic co-self-assembly, on the patterned surface whereby the composite can conform to the surface pattern to form the vertically oriented pore structure, the surface pattern on the film having a close lattice match to the composite; and 
 selectively removing one component of the composite to form a pattern of pores corresponding in location to said pattern of components. 
 
     
     
       12. The method of  claim 11  in which the pattern on the film surface is hexagonal. 
     
     
       13. The method of  claim 11  in which the film is an oxide film. 
     
     
       14. A method for producing an inorganic film having pores oriented normal to the plane of a surface of the film, comprising;
 forming a pattern of contrasting hydrophobicity and/or hydrophilicity on the film surface; 
 growing an inorganic/organic composite layer, by inorganic/organic co-self-assembly, on the patterned surface whereby the composite can conform to the surface pattern to form vertically oriented pore structures, in which the vertically oriented pore structures are hexagonally arranged, the surface pattern on the film being hexagonal with a close lattice match to the composite; and 
 treating the composite to remove the organic part of the composite to form a pattern of pores corresponding in location to said pattern. 
 
     
     
       15. The method of  claim 14  in which the composite layer comprises any polymer or surfactant templated hexagonal patterned material grown on any hexagonal surface pattern produced through self-assembly. 
     
     
       16. The method of  claim 14  in which the film is an oxide film. 
     
     
       17. The method of  claim 14  in which the surface pattern is made up of hydrophobic patches on a hydrophilic film surface. 
     
     
       18. The method of  claim 14  in which the surface pattern is made up of hydrophilic patches on a hydrophobic film surface. 
     
     
       19. The method of  claim 14  in which the components are formed by crosslinking, then calcining, the self-assembled components. 
     
     
       20. The method of  claim 14  in which the composite layer comprises silica on a titania patterned surface.